Rotors for compressing machines such as centrifugal blowers and pumps



A. BUCHI June 25, 1957 2 Sheets-Sheet 1 ROTORS FOR COMPRESSING MACHINES SUCH AS CENTRIFUGAL.

' BLOWERS AND PUMPS Original Filed Deo.'30, 1947 INVENTOR ALFRED BUCHI ATTORNEYS June 25, 1957 A. BUCHI 2,796,836

ROTORS FOR COMPRESSING CHINES .SUCH AS CENTRIFUGAL. BLOWE AND PUMPS Original Filed Deo.-30, 1947 2 Sheets-Sheet 2 INVENTOR ALFRED BUCHI B Wmpazw m ATTORNEYS United States Patent ROTORS FOR COMPRESSING MACHINES SUCH AS CENTRIFUGAL BLOWERS AND PUMPS Alfred Biichi, Winterthur, Switzerland Original application December 30, 1947, Serial No. 794,506, new Patent No. 2,652,191, dated September 15, 1953. Divided and this application July 19, 1952, Serial No. 305,237

Section 1, Public Law 690, August 8, 1946. Patent expires February 21, 1962 3 Claims. (Cl. 103-115) This invention relates to rotors for compressing machines such as centrifugal blowers and pumps.

This application is a division of application Serial No. 794,506 filed December 30, 1947, which is now Patent No. 2,652,191.

According to the present invention the rotor is composed of a driving disc and a closure disc overlying the latter each of said discs being integral with a section of the rotor blading and each of the complementary rotor blading sections having interengaging axially directed oflfsets. The blade ends of the two rotor sections may interengage with each other also in the radial direction. The two rotor sections are interconnected in the axial direction by connection elements. The rotor blades are, advantageously, provided with widened cross sectional portions adjacent to tenon shaped offset portions as well as at the points where the connection elements are situated. Towards the base portions the cross section of the blades is, advantageously, enlarged. With a view to providing for uniform thickness of the blade section at the joint the jointing portions about the blading may be offset in both rotor sections relative to the blade base surfaces in such manner that for the manufacture of the dies for the blading, that is, for the machining of the blading itself by means of conical milling cutters the latter can be guided along the joint at a uniform distance from their axes of rotation. The two rotor portions can be produced by being milled out of solid material or in the form of a casting or a pressed piece.

Several embodiments of the invention are illustrated in the accompanying drawings, by way of example only, in which Fig. 1 shows a cross section of a single stage centrifugal blower on the line I-I in Fig. 2;

Fig. 2 shows cross section of the same blower but on the line II--II in Fig. 1, and

Figs. 3, 4 and 5 are views of various details of the subject matter of the invention.

In Fig. 1 the rotor driving disc is designated by 1 and by 2 a closure disc overlying the same is referred to. The driving disc 1 is keyed to the driving shaft 3 by means of keys 4. The rotor 1, 2 is inclosed in a two-part casing 5, 6 including an entrance funnel 7, a spiral collecting space 8 and a delivery pipe connection 9. According to the invention the joint surface 10 between the two rotor sections 1 and 2 extending between the blading sections 11, 12 on said sections 1, 2 is stepped off in tenon shape so that a projection 13 on the blading section 12 fits in an all around tight manner in a recess 14 in the blading section 11. For securing this tight fit connection elements 15 protrude through the two rotor sections. These connection elements 15 extend through the blading sections 11 and 12 up to outer sides 16 and 17 of the driving disc 1 and the closure disc 2 respectively. Advantageously, said elements are riveted down at their ends. The conp l C nection elements 15 are dimensioned so as to be capable of resisting the resulting axial and tangential strains.

In Fig. 2 the driving rotor section 1 is shown as Well as individual blade sections 11 that are integral therewith and are provided with recesses 14 substantially in the middle thereof. The numeral 15 represents again the connection elements protruding through the blades.

In Fig. 3 the joint surface 10 is provided with only one projecting oifset 13 at the blade portions for interfitting in the axial direction with a recess 14' in the individual blade sections 11.

Fig. 4 depicts another embodiment of the invention. The joint surface 18 thereof is S-shaped. A radially inwardly projecting nose 13 on the blade sections 12 engages in a recess 14" in the blade sections 11 of the rotor body 1. The assembling of such a rotor is effected by axially pushing the rotor sections 1, 2 into position of interengagement until the noses 13" can be pushed into the recesses 14 in the tangential direction, that is, in the manner of a bayonet joint.

Fig. 5, being a tangential section of the two rotor portions 1 and 2 within the embrace of the blade sections 11, 12 thereof, shows by the double arrows 20 and 20 on these sections that the blade thickness is smaller at the joint surface 10 than at their bases 23 where said bases merge in the rotor discs 1 or 2. At the joint surface 10 the blade sections have in both rotor sections 1, 2 approximately the same thickness. The joint surface 10 may mutually interengage each other in any other suitable manner, for example, be dove-tailed to each other. Alternatively, several projections 13 and recesses 14 may be consecutively arranged in the radial direction.

The offsets are arranged in the jointing portions of the blades, advantageously, suchwise, that the rotor section less strained limits the stressing and the expansion of the higher strained rotor section by means of the jointing portions situated Within the blades.

The arrangement may also be such that the rotor section less strained is shrunk on the higher strained rotor section, for example, by pressing or hot shrinking said sections into engagement with each other at their jointing portions provided within the blading. By this means the rotor section being ordinarily higher strained in the condition of operation is still more relieved of straining to which it is otherwise subjected, whereas the rotor section less strained is subjected to increased straining. Again, the jointing portions may also be configurated in any other suitable manner than that shown.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A rotor for compressing machines such as centrifugal blowers and pumps comprising two sections confronting each other axially, one of said sections comprising a driving disc, blading port-ions extending partially axially from said disc, each of said blading portions being integral therewith, and the other section comprising a shroud ring,

blading portions on said shroud ring integral therewith and extending toward said first mentioned blading portions to abut thereagainst, offset joint edges substantially rectangular to the axis of rotation of the rotor and defining said blading portions in axial direction, said ofli'set joint edges upon each blading portion forming in radial direction two tangentially arranged integral inner and outer sub-portions of each said blading portions, an inner sub-portion of one of said blading portions and an outer sub-portion of the other of said blading portions being provided at the point of radial tangential transition with a tangentially radially directed nose for engaging each of the other opposing blading portions, the joint between said outer sub-portions being closer to said driv- 3 ing disc than the joint between said inner sub-portions whereby a coupling of said two rotor sections may be effected by holding them axially opposite one another and then by a relative turning of said sections said noses may be brought into interengagement as a bayonet joint 5 and thereby said blading portions are displaced into circumferentially matching position.

2. The rotor as set forth in claim 1 wherein pin means for shrinking said shroud ring section upon said driving disc section References Cited in the file of this patent UNITED STATES PATENTS 1,212,262 Rockwell Jan. 16, 1917 1,318,091 Jungstrom Oct. 7, 1919 2,366,251 Fullemann Jan. 2, 1945 FOREIGN PATENTS 394,001 Great Britain June 19, 1933 

